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1# LSST Data Management System 

2# Copyright 2008, 2009, 2010 LSST Corporation. 

3# 

4# This product includes software developed by the 

5# LSST Project (http://www.lsst.org/). 

6# 

7# This program is free software: you can redistribute it and/or modify 

8# it under the terms of the GNU General Public License as published by 

9# the Free Software Foundation, either version 3 of the License, or 

10# (at your option) any later version. 

11# 

12# This program is distributed in the hope that it will be useful, 

13# but WITHOUT ANY WARRANTY; without even the implied warranty of 

14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

15# GNU General Public License for more details. 

16# 

17# You should have received a copy of the LSST License Statement and 

18# the GNU General Public License along with this program. If not, 

19# see <http://www.lsstcorp.org/LegalNotices/>. 

20# 

21 

22""" 

23todo: Consider tweaking pixel scale so the average scale is as specified, 

24rather than the scale at the center. 

25""" 

26 

27__all__ = ["BaseSkyMapConfig", "BaseSkyMap"] 

28 

29import hashlib 

30import struct 

31 

32import lsst.geom as geom 

33import lsst.pex.config as pexConfig 

34from lsst.geom import SpherePoint, Angle, arcseconds, degrees 

35from . import detail 

36 

37 

38class BaseSkyMapConfig(pexConfig.Config): 

39 patchInnerDimensions = pexConfig.ListField( 

40 doc="dimensions of inner region of patches (x,y pixels)", 

41 dtype=int, 

42 length=2, 

43 default=(4000, 4000), 

44 ) 

45 patchBorder = pexConfig.Field( 

46 doc="border between patch inner and outer bbox (pixels)", 

47 dtype=int, 

48 default=100, 

49 ) 

50 tractOverlap = pexConfig.Field( 

51 doc="minimum overlap between adjacent sky tracts, on the sky (deg)", 

52 dtype=float, 

53 default=1.0, 

54 ) 

55 pixelScale = pexConfig.Field( 

56 doc="nominal pixel scale (arcsec/pixel)", 

57 dtype=float, 

58 default=0.333 

59 ) 

60 projection = pexConfig.Field( 

61 doc="one of the FITS WCS projection codes, such as:" 

62 "- STG: stereographic projection" 

63 "- MOL: Molleweide's projection" 

64 "- TAN: tangent-plane projection", 

65 dtype=str, 

66 default="STG", 

67 ) 

68 rotation = pexConfig.Field( 

69 doc="Rotation for WCS (deg)", 

70 dtype=float, 

71 default=0, 

72 ) 

73 

74 

75class BaseSkyMap: 

76 """A collection of overlapping Tracts that map part or all of the sky. 

77 

78 See TractInfo for more information. 

79 

80 Parameters 

81 ---------- 

82 config : `BaseSkyMapConfig` or None (optional) 

83 The configuration for this SkyMap; if None use the default config. 

84 

85 Notes 

86 ----- 

87 BaseSkyMap is an abstract base class. Subclasses must do the following: 

88 define ``__init__`` and have it construct the TractInfo objects and put 

89 them in ``__tractInfoList__`` define ``__getstate__`` and ``__setstate__`` 

90 to allow pickling (the butler saves sky maps using pickle); 

91 see DodecaSkyMap for an example of how to do this. (Most of that code could 

92 be moved into this base class, but that would make it harder to handle 

93 older versions of pickle data.) define updateSha1 to add any 

94 subclass-specific state to the hash. 

95 

96 All SkyMap subclasses must be conceptually immutable; they must always 

97 refer to the same set of mathematical tracts and patches even if the in- 

98 memory representation of those objects changes. 

99 """ 

100 

101 ConfigClass = BaseSkyMapConfig 

102 

103 def __init__(self, config=None): 

104 if config is None: 

105 config = self.ConfigClass() 

106 config.freeze() # just to be sure, e.g. for pickling 

107 self.config = config 

108 self._tractInfoList = [] 

109 self._wcsFactory = detail.WcsFactory( 

110 pixelScale=Angle(self.config.pixelScale, arcseconds), 

111 projection=self.config.projection, 

112 rotation=Angle(self.config.rotation, degrees), 

113 ) 

114 self._sha1 = None 

115 

116 def findTract(self, coord): 

117 """Find the tract whose center is nearest the specified coord. 

118 

119 Parameters 

120 ---------- 

121 coord : `lsst.geom.SpherePoint` 

122 ICRS sky coordinate to search for. 

123 

124 Returns 

125 ------- 

126 result : `TractInfo` 

127 TractInfo of tract whose center is nearest the specified coord. 

128 

129 Notes 

130 ----- 

131 - If coord is equidistant between multiple sky tract centers then one 

132 is arbitrarily chosen. 

133 

134 - The default implementation is not very efficient; subclasses may wish 

135 to override. 

136 

137 **Warning:** 

138 If tracts do not cover the whole sky then the returned tract may not 

139 include the coord. 

140 """ 

141 distTractInfoList = [] 

142 for i, tractInfo in enumerate(self): 

143 angSep = coord.separation(tractInfo.getCtrCoord()).asDegrees() 

144 # include index in order to disambiguate identical angSep values 

145 distTractInfoList.append((angSep, i, tractInfo)) 

146 distTractInfoList.sort() 

147 return distTractInfoList[0][2] 

148 

149 def findTractPatchList(self, coordList): 

150 """Find tracts and patches that overlap a region. 

151 

152 Parameters 

153 ---------- 

154 coordList : `list` of `lsst.geom.SpherePoint` 

155 List of ICRS sky coordinates to search for. 

156 

157 Returns 

158 ------- 

159 reList : `list` of (`TractInfo`, `list` of `PatchInfo`) 

160 For tracts and patches that contain, or may contain, the specified 

161 region. The list will be empty if there is no overlap. 

162 

163 Notes 

164 ----- 

165 **warning:** 

166 This uses a naive algorithm that may find some tracts and patches 

167 that do not overlap the region (especially if the region is not a 

168 rectangle aligned along patch x, y). 

169 """ 

170 retList = [] 

171 for tractInfo in self: 

172 patchList = tractInfo.findPatchList(coordList) 

173 if patchList: 

174 retList.append((tractInfo, patchList)) 

175 return retList 

176 

177 def findClosestTractPatchList(self, coordList): 

178 """Find closest tract and patches that overlap coordinates. 

179 

180 Parameters 

181 ---------- 

182 coordList : `lsst.geom.SpherePoint` 

183 List of ICRS sky coordinates to search for. 

184 

185 Returns 

186 ------- 

187 retList : `list` 

188 list of (TractInfo, list of PatchInfo) for tracts and patches 

189 that contain, or may contain, the specified region. 

190 The list will be empty if there is no overlap. 

191 """ 

192 retList = [] 

193 for coord in coordList: 

194 tractInfo = self.findTract(coord) 

195 patchList = tractInfo.findPatchList(coordList) 

196 if patchList and not (tractInfo, patchList) in retList: 

197 retList.append((tractInfo, patchList)) 

198 return retList 

199 

200 def __getitem__(self, ind): 

201 return self._tractInfoList[ind] 

202 

203 def __iter__(self): 

204 return iter(self._tractInfoList) 

205 

206 def __len__(self): 

207 return len(self._tractInfoList) 

208 

209 def __hash__(self): 

210 return hash(self.getSha1()) 

211 

212 def __eq__(self, other): 

213 try: 

214 return self.getSha1() == other.getSha1() 

215 except AttributeError: 

216 return NotImplemented 

217 

218 def __ne__(self, other): 

219 return not (self == other) 

220 

221 def logSkyMapInfo(self, log): 

222 """Write information about a sky map to supplied log 

223 

224 Parameters 

225 ---------- 

226 log : `lsst.log.Log` 

227 Log object that information about skymap will be written 

228 """ 

229 log.info("sky map has %s tracts" % (len(self),)) 

230 for tractInfo in self: 

231 wcs = tractInfo.getWcs() 

232 posBox = geom.Box2D(tractInfo.getBBox()) 

233 pixelPosList = ( 

234 posBox.getMin(), 

235 geom.Point2D(posBox.getMaxX(), posBox.getMinY()), 

236 posBox.getMax(), 

237 geom.Point2D(posBox.getMinX(), posBox.getMaxY()), 

238 ) 

239 skyPosList = [wcs.pixelToSky(pos).getPosition(geom.degrees) for pos in pixelPosList] 

240 posStrList = ["(%0.3f, %0.3f)" % tuple(skyPos) for skyPos in skyPosList] 

241 log.info("tract %s has corners %s (RA, Dec deg) and %s x %s patches" % 

242 (tractInfo.getId(), ", ".join(posStrList), 

243 tractInfo.getNumPatches()[0], tractInfo.getNumPatches()[1])) 

244 

245 def getSha1(self): 

246 """Return a SHA1 hash that uniquely identifies this SkyMap instance. 

247 

248 Returns 

249 ------- 

250 sha1 : `bytes` 

251 A 20-byte hash that uniquely identifies this SkyMap instance. 

252 

253 Notes 

254 ----- 

255 Subclasses should almost always override ``updateSha1`` instead of 

256 this function to add subclass-specific state to the hash. 

257 """ 

258 if self._sha1 is None: 

259 sha1 = hashlib.sha1() 

260 sha1.update(type(self).__name__.encode('utf-8')) 

261 configPacked = struct.pack( 

262 "<iiidd3sd", 

263 self.config.patchInnerDimensions[0], 

264 self.config.patchInnerDimensions[1], 

265 self.config.patchBorder, 

266 self.config.tractOverlap, 

267 self.config.pixelScale, 

268 self.config.projection.encode('ascii'), 

269 self.config.rotation 

270 ) 

271 sha1.update(configPacked) 

272 self.updateSha1(sha1) 

273 self._sha1 = sha1.digest() 

274 return self._sha1 

275 

276 def updateSha1(self, sha1): 

277 """Add subclass-specific state or configuration options to the SHA1. 

278 

279 Parameters 

280 ---------- 

281 sha1 : `hashlib.sha1` 

282 A hashlib object on which `update` can be called to add 

283 additional state to the hash. 

284 

285 Notes 

286 ----- 

287 This method is conceptually "protected" : it should be reimplemented by 

288 all subclasses, but called only by the base class implementation of 

289 `getSha1` . 

290 """ 

291 raise NotImplementedError() 

292 

293 SKYMAP_RUN_COLLECTION_NAME = "skymaps" 

294 

295 SKYMAP_DATASET_TYPE_NAME = "skyMap" 

296 

297 def register(self, name, butler): 

298 """Add skymap, tract, and patch Dimension entries to the given Gen3 

299 Butler. 

300 

301 Parameters 

302 ---------- 

303 name : `str` 

304 The name of the skymap. 

305 butler : `lsst.daf.butler.Butler` 

306 The butler to add to. 

307 

308 Raises 

309 ------ 

310 lsst.daf.butler.registry.ConflictingDefinitionError 

311 Raised if a different skymap exists with the same name. 

312 

313 Notes 

314 ----- 

315 Registering the same skymap multiple times (with the exact same 

316 definition) is safe, but inefficient; most of the work of computing 

317 the rows to be inserted must be done first in order to check for 

318 consistency between the new skymap and any existing one. 

319 

320 Re-registering a skymap with different tract and/or patch definitions 

321 but the same summary information may not be detected as a conflict but 

322 will never result in updating the skymap; there is intentionally no 

323 way to modify a registered skymap (aside from manual administrative 

324 operations on the database), as it is hard to guarantee that this can 

325 be done without affecting reproducibility. 

326 """ 

327 nxMax = 0 

328 nyMax = 0 

329 tractRecords = [] 

330 patchRecords = [] 

331 for tractInfo in self: 

332 nx, ny = tractInfo.getNumPatches() 

333 nxMax = max(nxMax, nx) 

334 nyMax = max(nyMax, ny) 

335 region = tractInfo.getOuterSkyPolygon() 

336 centroid = SpherePoint(region.getCentroid()) 

337 tractRecords.append({ 

338 "skymap": name, 

339 "tract": tractInfo.getId(), 

340 "region": region, 

341 "ra": centroid.getRa().asDegrees(), 

342 "dec": centroid.getDec().asDegrees(), 

343 }) 

344 for patchInfo in tractInfo: 

345 cellX, cellY = patchInfo.getIndex() 

346 patchRecords.append({ 

347 "skymap": name, 

348 "tract": tractInfo.getId(), 

349 "patch": tractInfo.getSequentialPatchIndex(patchInfo), 

350 "cell_x": cellX, 

351 "cell_y": cellY, 

352 "region": patchInfo.getOuterSkyPolygon(tractInfo.getWcs()), 

353 }) 

354 skyMapRecord = { 

355 "skymap": name, 

356 "hash": self.getSha1(), 

357 "tract_max": len(self), 

358 "patch_nx_max": nxMax, 

359 "patch_ny_max": nyMax, 

360 } 

361 butler.registry.registerRun(self.SKYMAP_RUN_COLLECTION_NAME) 

362 # Kind of crazy that we've got three different capitalizations of 

363 # "skymap" here, but that's what the various conventions (or at least 

364 # precedents) dictate. 

365 from lsst.daf.butler import DatasetType 

366 datasetType = DatasetType( 

367 name=self.SKYMAP_DATASET_TYPE_NAME, 

368 dimensions=["skymap"], 

369 storageClass="SkyMap", 

370 universe=butler.registry.dimensions 

371 ) 

372 butler.registry.registerDatasetType(datasetType) 

373 with butler.transaction(): 

374 if butler.registry.syncDimensionData("skymap", skyMapRecord): 

375 butler.registry.insertDimensionData("tract", *tractRecords) 

376 butler.registry.insertDimensionData("patch", *patchRecords) 

377 butler.put(self, datasetType, {"skymap": name}, run=self.SKYMAP_RUN_COLLECTION_NAME)